Mechanical Engineering Commons^™

Alteration Of Peripheral Cytokines In Alzheimer’S Disease, Zhengshi Yang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with the clinical symptoms of gradual cognitive decline and memory loss. Biologically, abnormal accumulation of Aβ (Aβ) plaque and tau tangles in the brain are the core pathological hallmarks in AD. Although inflammatory response is not specific to AD, emerging evidence suggests that the disrupted innate immune system within the central nervous system, particularly microglial activation, might act as the bridge linking Aβ aggregation to pathological phosphorylation and aggregation of tau. The inflammatory response was suggested to initially have a neuroprotective role of attempting to clear Aβ plaques, and then become neurotoxic …

Expandable And Retractable Wheel Design, Ethan Fortenberry, Emily Cottrell, Keegan Martin, Benjamin Mcconnell

Mechanical Engineering

Our sponsor, Jeremy Goren, wants to see his patented expandable wheel design come to life. He requires a functional final product actuated by linear actuators and with a continuous, circular outer shell. The overall design can be broken up into 2 parts: the inner hub and outer shell. The wheel's shell will consist of a 12-piece outer shell that guides the 6 inner shell pieces. The outer shell pieces will be connected via a UBracket. The hub will consist of 3 identical parts that will hold 2 linear actuators each. The pieces will be bolted together to create 1 singular …

The Waterbug: Adaptive Paddle Board Frame, Remy James Elio Lacchia, Katie Kellum, Madeline Evenson, Shelbi Sullaway

Mechanical Engineering

People with disabilities, particularly wheelchair users, face limitations in participating in outdoor activities like paddleboarding. Central Cal Adaptive, a nonprofit organization, aims to bridge this gap by offering adapted paddleboarding experiences. However, their current paddleboard presents challenges such as portability, range of motion, stability, and safety. Our team, comprising Madeline Evenson, Remy Lacchia, Katie Kellum, and Shelbi Sullaway, has collaborated with Central Cal Adaptive to refine the existing paddleboard design. The team’s goal is to enhance the paddleboard's functionality to better cater to wheelchair users' needs, ensuring lightweight, portable, and safe features for an improved outdoor experience.

Our paddleboard concept …

Piston Crown Design, Kurt L. Lippmann, Liam T. Janssen, Alex Rangel, Larry J. Davis

Mechanical Engineering

This project investigates the effects of dimpling a piston crown, and its impact on engine combustion dynamics. Through computational methods, the effects of piston crown dimpling on flow characteristics were evaluated. Theoretical results were verified with experimental methods. Experimental methods included characterization of exhaust gas content, engine horsepower and torque, and exhaust opacity.

Swim Fly Drone, Alia Wolken, Sha'anan Levy, Andrew Jwaideh, Eduardo Santos

Mechanical Engineering

This project addresses the need for a versatile drone that is capable of operation in both air and water environments, with potential applications in infrastructure inspection, defense, search and rescue, and ocean exploration. This project focuses on the design and development of a waterproof aerial drone capable of floating on the water surface and submerging underneath to controlled depths with the integration of a custom detachable buoyancy chamber. The buoyancy chamber design utilizes syringes to compress and decompress air inside of the chamber, changing the volume of the chamber, with an actuation system controlled by a closed-loop control system that …

Development Of A Manifold Microchannel Heat Sink For The Electrification Of Aircraft, Joshua Mora Sanchez

Mechanical Engineering Undergraduate Honors Theses

The miniaturization of microprocessors and power electronics is leading to critical thermal management challenges. For instance, the heat flux generated in modern computer chips is at the order of 100W/cm², which is well beyond the limit of air cooling. This high heat generation can cause a variety of thermal or mechanical failures in electronic devices. As such, there is a pressing need to devise effective cooling strategies for these microelectronic devices. Liquid cooling with microchannel heat sinks is a promising technology for high power loads. Nevertheless, traditional heat sinks with straight microchannels suffer from two critical challenges: high pressure drop …

Neodymium Doped Zinc Oxide Based Advanced Flexible Piezoelectric Energy Harvester And Self-Powered Biomotion Sensor, Muhtasim Ul Karim Sadaf, Abu Musa Abdullah, Haimanti Majumder, Sk Shamim Hasan Abir, Mariana Torres, Karen Lozano, Md. Wasikur Rahman, M. Jasim Uddin

Mechanical Engineering Faculty Publications

Flexible piezoelectric devices have garnered a lot of attention for their potential as energy harvesters and transducers. In this work, Neodymium (Nd) doped Zinc Oxide (ZnO) based flexible piezoelectric energy harvester and sensory device has been developed. Nd-doped ZnO has been synthesized using wet chemical co-precipitation and incorporated in Polyvinylidene Difluoride (PVDF) polymer matrix along with Multiwalled Carbon Nanotubes (MWCNT) to produce flexible piezoelectric films. The piezoelectric output of the device is tested at variable tapping frequency (60 to 240 BPM) and pressure (10 to 40 psi). The device has also been tested with conventional electronics like bridge rectifiers, capacitors, …

Investigation Ionic Polymer Metal Composite Capacitors Through Fabrication, Experimentation, And Modeling, Liya S. Napollion

UNLV Theses, Dissertations, Professional Papers, and Capstones

The increasing demand for greater energy storage capacity alongside the need to minimize the size of various devices, such as hybrid electric vehicles, medical devices, and pulsed power systems—has highlighted the necessity for advanced polymer film capacitors with high energy density. While traditional batteries and electronic devices have generally sufficed for many applications, their inherent size limitations hinder their ability to deliver the high levels of peak power required for certain demanding applications. This shortfall highlights the critical ongoing challenge within the energy storage sector to improve technology and more effectively meet these growing power requirements. Flexible Ionic Polymer Metal …

Primary And Secondary Resonances Of Fringe Effect Electrostatically Actuated Mems Cantilever Resonators, Miguel Armando Martinez

Theses and Dissertations

The nonlinear dynamics of micro-electromechanical system (MEMS) cantilever resonators actuated by the fringe field at parametric and primary resonances are studied. Three models are used based on different descriptions of the system capacitance. In the fringe and capacitance models, the electrostatic force due to the parallel-plate capacitance is neglected due to a hole in the ground plate (removes overlapping area). The SolidWorks model is based on numerical capacitance simulations performed on SolidWorks using EMS. All three models that approximate the fringe field capacitance are compared with one another. The Method of Multiple Scales (MMS) and Reduced Order Model (ROM) up …

Resonances Of Electrostatically Actuated Non-Uniform Mems Cantilever Resonator Of Constant Width And Linearly Varying Thickness, Rigoberto Flores

Theses and Dissertations

In this investigation the behavior of an electrostatically actuated non-uniform microelectromechanical (MEMS) cantilever resonator of constant width and linearly varying thickness is investigated. The cantilever resonator vibrates using soft AC voltage at near half the first natural frequency of the cantilever and near the first natural frequency of the cantilever, known as primary and parametric resonances, respectively. Bifurcation diagrams for the amplitude-frequency and amplitude-voltage response are obtained for both resonances. Two methods are used in this investigation, namely the Method of Multiple Scales (MMS) and Reduced Order Model (ROM) using up to 6 modes of vibration.

These methods are used …

Thermal Conductivity Characterization Of High Oleic Vegetable Oils Based Hybrid Nanofluids Formulated Using Gnp, Tio2, Mos2, Al2o3 Nanoparticles For Mql Machining, Anthony Chukwujekwu Okafor, Tobechukwu Kingsley Abor, Saidanvar Esanjonovich Valiev, Ignatius Echezona Ekengwu, Abiodun Saka, Monday Uchenna Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents the results of thermal conductivity characterization of six high oleic soybean oil (HOSO) and four high oleic canola oil (HOCO)-based hybrid nanofluids formulated with four types of nanoparticles (Graphene nanoplatelet (xGnP), TiO2, MoS2, and Al2O3) at nanoparticles wt.% concentration from 1 % to 7 % in 1 % increment using the two-step method for use in MQL machining of difficult-to-cut metals. Thermal conductivity of the formulated hybrid nanofluids were measured using Thermtest Transient Hot Wire Liquid Thermal Conductivity Meter at temperatures from 25 °C to 75 °C in increment of 10 °C. Obtained results showed that thermal …

Finite Element Analysis And Verification Of Transverse Mechanical Properties Of Generally Cylindrical Orthotropic Constitutive Modeling Of 3-Phase Nanocomposite Unit Cell, Christopher J. Hawkins

Master's Theses

Fiber-reinforced composites are increasingly popular due to their specific strength and stiffness, making them ideal for high-performance applications. However, these materials primarily exhibit superior properties in-plane, while their out-of-plane characteristics remain comparatively weaker. Previous research has shown that the most effective method to enhance out-of-plane properties involves the incorporation of carbon nanotubes. Experimental tests have demonstrated significant improvements in properties such as tension, flexural, short beam shear, and fracture toughness. Alongside these experimental studies, analytical equations have been developed to predict the behavior of these composites under various loading conditions, including tension, bending, shear, and fracture. Existing models primarily address …

Investigating Challenges Of Converting Cad Models To Game Ready Assets, Vathsa Pawar

All Theses

This thesis explores the challenges associated with converting detailed CAD models into game-ready assets optimized for use in virtual reality (VR) environments using game engines, focusing on enhancing using mechanical engineering models. The primary goal is to establish a toolchain that allows the integration of CAD models into game engines for immersive applications, enabling engineers and stakeholders to interact with 3D models in a synthetic environment. The study employs several test cases ranging from simple door models to complex automotive vehicle prototypes, elaborating the process of exporting CAD models through intermediate formats (such as STEP, STL, GLB) using tools like …

End-To-End Learning For A Low-Cost Robotics Arm, Abhishek Chothani

Theses and Dissertations

Robotic manipulation is a cornerstone of automation, with the ultimate goal of developing versatile systems capable of executing a wide range of real-world tasks autonomously. Traditional robotics approaches, while reliable and widely adopted in industrial settings, often struggle with adaptability, perception, and dynamic task execution. This thesis explores the evolution from classical robotics techniques to modern learning-based approaches, leveraging advancements in artificial intelligence to overcome these limitations.

Initially, the thesis presents a pick-and-place pipeline built using the Drake robotics framework and the KUKA iiwa robotic arm. This system employs a pseudoinverse controller for inverse kinematics to perform structured tasks like …

Fabrication And Performance Of Scalable Bio-Engineered Porous Layers For Efficient Co2 Capture, Mary Sharon Rose Bondugula

Theses and Dissertations

This dissertation addresses the critical challenge of mitigating climate change by advancing CO2 capture technologies. As global CO2 emissions continue to rise, effective methods for capturing and separating CO2 from industrial processes are essential to combat climate change. Existing CO2 capture systems, such as Pressure Swing Adsorption (PSA) and Temperature Swing Adsorption (TSA), often rely on packed bed designs that face limitations, including poor heat and mass transfer, slow gas diffusion, and low thermal conductivity, reducing their efficiency. To overcome these challenges, this dissertation explores innovative solutions by developing advanced adsorbent coatings and scalable bed configurations.

This research begins by …

Fabrication And Charcaterization Of Pullulan-Collagen Nanofibers Via Forcespinning, Valeria Leon Leal

Theses and Dissertations

Extensive research on collagen has spurred advancements in tissue engineering and biomaterial development, given collagen´s pivotal role in regulating various tissue structures across diverse organisms. This study delves into fabricating nanocomposites utilizing collagen, along with silver nanoparticles, chondroitin sulfate and pullulan, for potential applications in antibacterial medical devices, and cell regeneration. Collagen, abundant in the extracellular matrix, provides essential structural support, while silver nanoparticles and chondroitin confer antimicrobial properties, crucial for combating infections. Pullulan, a polysaccharide polymer, serves as a biocompatible carrier for silver nanoparticles whilst being the starting nanofiber forming material. Utilizing Forcespinning® technology, composite nanofibers were successfully synthesized. …

Synthesis Of Materials For Additive Manufacturing Of Enhanced Polymers And Textured Ceramics, Diana Fontes

Open Access Theses & Dissertations

This research will be divided into two sections. The first section investigates the development of textured Barium Titanate (BaTiO3) ceramics fabricated through Direct Ink Write Printing (DIW) integrated with Templated Grain Growth (TGG). This approach aims to develop lead-free piezoelectric materials with grain alignment during printing process to promote high piezoelectric performance comparable to those in lead-based ceramics. This research evaluates the impact of the DIW-TGG process on grain orientation, material densification, and piezoelectric response, illustrating its potential for developing high-performance ceramics for advanced applications such as sensors, actuators, and other piezoelectric devices. The second project explores the chemical stability …

Vertically Aligned Nickel Cobalt Molybdenum Copper Oxide Nanotubes For High Performance Asymmetric Supercapacitors, Ricardo Herrera Aguirre

Open Access Theses & Dissertations

Designing materials having novel multi metal oxide electrodes with controlled structure and composition is a critical technological challenge for high performance supercapacitor applications. Quaternary metal oxides have attracted considerable attention in this field, where many methods have been used to improve their performance. In the present work, the nickel cobalt molybdenum copper oxide (NCMCuO2) has been synthesized using a hydrothermal method. The effect of different concentrations of Cu doping (0.5%,1.0% and 2.0%) on the NCM frame and structural and electrochemical properties of the quaternary metal oxide (NCMCuO2) are studied thoroughly. The XRD pattern of synthesized NCMCuO2 exhibited predominant (002) orientation …

Thermal Analysis Of Combustion Synthesis Of Fealxoy Catalysts For Dehydrogenation Of Fossil Fuels, Laura Alejandra Martinez Espinoza

Open Access Theses & Dissertations

The growing demand for hydrogen as a clean energy carrier highlights the need for its alternative production method with reduced CO₂ emissions. Microwave-assisted thermocatalytic dehydrogenation of fossil fuels offers a promising solution for clean hydrogen production, with FeAlxOy nanocomposites acting as efficient catalysts due to their thermal stability, catalytic activity, and microwave-absorption properties. FeAlxOy nanocomposites, fabricated by solution combustion synthesis (SCS), have shown good microwave-absorption and catalytic properties. However, the effects of synthesis parameters such as fuel type and Fe:Al molar ratio on the SCS process and properties of the final material are not well understood. The SCS process involves …

Elucidating The Effect Of Milled Glass And Graphite Fiber On The Quasi-Static Properties Of Vinyl Ester Resin Composites, Sarahi Mendivil

Open Access Theses & Dissertations

Composite materials can be tailored to various applications, making them one of the most conventional materials. Their ability to enhance desired characteristics enables higher strength while maintaining light weight. However, understanding defects and manufacturing limitations is crucial for optimizing their fabrication processes. This paper focuses on the manufacturing processes of open molding with controlled variations to establish an optimal technique aimed at minimizing defects, such as bubble formation where the focus is on mitigating defects and ensuring uniform dispersion of fiber in fiber-reinforced composites. After refining the manufacturing process, composites with varying resin-to-fiber concentration ratios were manufactured using glass and …

Ultra-High Temperature Ceramics: Materials, Manufacturing, And Machine Development, Joseph Matthew Munoz

Open Access Theses & Dissertations

This research aimed to advance the 3D printing of ultra-high-temperature ceramic matrix composites (UHTCMCs) and develop a custom Direct Ink Writing (DIW) system with multimaterial and in-line mixing capabilities. The study first focused on creating ZrB₂–SiC composites reinforced with aligned silicon carbide fibers (SiCf) using paste extrusion. By formulating suspensions with a preceramic polymer (SMP-10), ZrB₂, and SiCf, the study assessed how fiber alignment influenced key properties such as thermal and electrical conductivity and mechanical strength. Green curing and pyrolysis transformed the printed parts into UHTCMCs, with results showing substantial improvements in thermal conductivity—nearly double that of non-aligned parts—and a …

A Blue Hydrogen Framework For Regional Energy Resiliency, Safwan Shafquat

Open Access Theses & Dissertations

High-pressure gasification is gaining attention as an emerging solution for sustainable energy production due to its potential to achieve higher efficiencies, improved syngas quality and smaller equipment footprints. High operating pressures and temperatures can increase the synergistic reactivity of biomass and organic materials, consequently enabling higher in situ tar reformation and ultimately reducing the number of gas treatment requirements. Additionally, higher operating pressures result in a more concentrated CO2 stream and reduce the amount of post-gasification compression requirements in the carbon capture and storage (CCS) unit, improving overall system efficiency. Plus, pressurized CO2 streams from the gasifier also provides routes …

Modeling And Understanding Of Additive Manufacturing Periodic Cellular Structures With Heterogeneity: Property, Quality And Design Strategy., Naresh Koju

Electronic Theses and Dissertations

Lightweight cellular structures with their higher per mass performance capability, multifunctional designability and property tolerability are gaining much wider adaptation in many engineering applications ranging from aerospace, defense, biomedical, automotive to sports. However, to achieve the desired performance levels careful design must be carried out. The experimental-based empirical design often involves high manufacturing cost, and there are also certain information/knowledges about the cellular deigns that could not be easily obtained experimentally, such as the deformation local fracture initiation. Similarly, numerical modeling-based design approach commonly suffers from high computation cost and the lack of inverse designability. In addition, numerical models often …

Delineating Genetic Influences On Neurodegenerative Disorders And Infectious Diseases Through Advanced Computational Methods, Xiaowei Zhuang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Genetics plays a critical role in understanding the molecular mechanisms underlying neurodegenerative disorders and pathogen evolution in infectious diseases. For example, identifying genetic variants associated with a disease phenotype uncovers functional pathways that could lead to potential drug targets and therapeutic interventions. In addition, tracking the genetic evolution of pathogens enables early detection and warning of infectious disease outbreaks. In both applications, given the large amount of genetic data, advanced computational methods, including longitudinal and multivariate models, could significantly boost the statistical power and capture interrelationships among traits, environmental factors and genetic influences. This dissertation focuses on four applications of …

Deformation Mechanism In Gold Nanoparticles Under Compressive Loading: Insights From Atomistic Modelling And Unsupervised Machine Learning, Tanuj Gupta

All Dissertations

Gold nanoparticles (AuNPs) offer exciting possibilities due to their inertness, malleability, and tunable structures, making them valuable for applications ranging from nanomedicine to electronics. Their optical, mechanical, and other properties can be tailored by modifying shape and structure, underscoring the importance of understanding their deformation behaviour at the nanoscale. This study used classical molecular dynamics simulations with LAMMPS to investigate the deformation mechanisms of gold nanospheres (AuNS) under uniaxial compression. Employing the embedded atom method (EAM) potential to model atomic interactions, AuNS with 20 nm in diameter were compressed along the z-direction using planar indenters moving at a constant …

Introducing The Second-Order Features Adjoint Sensitivity Analysis Methodology For Neural Ordinary Differential Equations—I: Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work introduces the mathematical framework of the novel “First-Order Features Adjoint Sensitivity Analysis Methodology for Neural Ordinary Differential Equations” (1st-FASAM-NODE). The 1st-FASAM-NODE methodology produces and computes most efficiently the exact expressions of all of the first-order sensitivities of NODE-decoder responses with respect to the parameters underlying the NODE’s decoder, hidden layers, and encoder, after having optimized the NODE-net to represent the physical system under consideration. Building on the 1st-FASAM-NODE, this work subsequently introduces the mathematical framework of the novel “Second-Order Features Adjoint Sensitivity Analysis Methodology for Neural Ordinary Differential Equations (2nd-FASAM-NODE)”. The 2nd-FASAM-NODE methodology efficiently computes the exact expressions …

Introducing The Second-Order Features Adjoint Sensitivity Analysis Methodology For Neural Ordinary Differential Equations—Ii: Illustrative Application To Heat And Energy Transfer In The Nordheim–Fuchs Phenomenological Model For Reactor Safety, Dan Gabriel Cacuci

Faculty Publications

This work presents an illustrative application of the newly developed “Second-Order Features Adjoint Sensitivity Analysis Methodology for Neural Ordinary Differential Equations (2nd-FASAM-NODE)” methodology to determine most efficiently the exact expressions of the first- and second-order sensitivities of NODE decoder responses to the neural net’s underlying parameters (weights and initial conditions). The application of the 2nd-FASAM-NODE methodology will be illustrated using the Nordheim–Fuchs phenomenological model for reactor safety, which describes a short-time self-limiting power transient in a nuclear reactor system having a negative temperature coefficient in which a large amount of reactivity is suddenly inserted. The representative model responses that will …

Understanding Failure Mechanisms For Two Colorectal Anastomosis Techniques, Youssef Sherif Sadek Fahmy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Colorectal Surgery continues to be one of the most common gastrointestinal surgeries performed in the US. A common complication known as Anastomotic Leakage (AL) that threatens up to 30% of patients with this surgery. Many cases of AL can decrease the quality of life for patients or extensively extend hospital stays, and in many cases, lead to death. Researchers have studied this complication in clinical trials, yet few studied the mechanics of stapled anastomosis in controlled environments. The purpose of this research was to understand the mechanical interaction between the staples and the tissue, and to eventually apply it in …

Control Of X-Delta Arm And Self-Leveling Robot Systems For Uav Applications, Prathibha Sobha

UNLV Theses, Dissertations, Professional Papers, and Capstones

The water droplet penetration test (WDPT) is an environmental assessment method for analyzing soil properties by measuring the penetration of water droplets into soil. This test provides insights into soil moisture retention and resilience, especially valuable in fire-prone or arid regions where soil recovery and erosion control are essential. Although this project does not conduct an actual WDPT, it investigates two key robotic systems designed to support such applications: an X-delta robot arm, which simulates precise droplet delivery patterns, and a self-leveling platform that ensures stability on uneven terrain, where the X-delta robot is mounted. Together, these systems examine the …

Mechanically Cost-Effective Approach For Bipedal Walking In Robots Using Instantaneous Collision Angle, Smit R. Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Humans, as bipedal locomotors, are effective at reducing the mechanical cost of transport (CoTmech) by adopting movement strategies and gaits that minimize energy expenditure for a given distance. By using different gaits at different speeds, leveraging their long spring-like tendons and muscle elasticity which store and release energy during movement, humans reduce the mechanical effort required for locomotion. Current locomotion solutions offered in bipedal robots, based on legacy walking and running gait models, are not great at energy efficiency unless walking at very low speeds. Additionally, the control system of robots, designed to ensure stability and adaptability, requires substantial resources, …